A 15-year-old boy has been found guilty of murdering another teenager by stabbing him to death after he went to a housing estate to try to retrieve a stolen mobile phone.

The Old Bailey heard Dogan Ismail, 17, was knifed through the heart after going with another 15-year-old to get back his BlackBerry phone from the Aylesbury estate, Walworth, south London, on December 30.

They confronted the defendant, who cannot be named for legal reasons, who was said to have gone into a flat and returned with a knife.

Prosecutor Brendan Finucane QC told jurors as he opened the trial last month: "After a few minutes, he came out again.

"This time he was holding a knife."

The defendant then walked straight up to Mr Ismail, stabbed him in the chest and walked away, the court heard.

Mr Ismail collapsed and died despite a doctor and paramedics giving him emergency treatment.

The youth disappeared but gave himself up to police two weeks later.

He had denied murder but admitted theft and manslaughter.

Wearing a blue jumper over a white shirt, he showed no emotion as the verdict was announced.